i)My explanation would be Game ID is the identity of a game! It should be unique and no two different games should share a same Game ID

ii)In order for the cheat codes to show up on your cheat menu, the Game ID of your database should be the same as your game’s Game ID! Otherwise you won’t see any codes on your cheat menu.

iii)A little addon from dsrules about game ID
"Game ID: is composed by two parts, the first 4 letters are for the game "Game code", the last 8 hexadecimal numbers for the game crc code, used for the match of the cheat and the corresponding game."

yes, M3Real also recognize the first 4 letters as the game id and the last 8 are ignored, that's why patched games with different crc code don't affect the M3Real or iTouch

iv)Common problem/mistake
For example a patched / dubbed rom’s Game ID might be different from the clean rom! If both the IDs are different it will cause cheats doesn’t show up on menu (this doesn't affect M3real or iTouch users)

v)Use the … function to locate the game ID! Where is the … ? It is in between of the Game ID and the Dup? button.

After Pressing the … button you will be presented a menu, locate your game and click OPEN. You will realized the default Game ID will change from ABCJ 12345678 to something else. This is the Game ID for Avalon Code YOGE 53AC1A52